1. Field of the Invention
This invention relates generally to antennas and more specifically to the structure of a multiple-frequency Z-type Inverted-F antenna of small size and improved gain.
2. Description of the Prior Art
Following the consumer driven trend towards smaller wireless communications devices, there is an ongoing need of increased miniaturization and increased functionality of antennas. Aside from manufacturing and assembly concerns, complicating the design process is the additional necessity of good gain performance for each of two or more frequencies, each having omni-directional radiation patterns, for convenient and reliable transmission and reception in today's wireless world.
Although many designs have been presented to solve these problems, they are still of a relatively large size, difficult to reproduce accurately, highly directional, suffer poor gain performance, especially in the 5 GHz area range, and/or offer narrow Voltage Standing Wave Ratio (VSWR) bandwidths amongst the frequencies.